package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    ISeckillVoucherService seckillVoucherService;
    @Resource
    RedisIdWorker redisIdWorker;
    @Resource
    StringRedisTemplate stringRedisTemplate;
    @Resource
    RedissonClient redissonClient;

    public static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    //private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);//阻塞队列
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();//线程池

    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //订单id
        long orderId = redisIdWorker.nextId("order");
        //1、执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(),String.valueOf(orderId)
        );
        int r = result.intValue();
        //2、判断结果是否为0
        if (r != 0) {
            //2.1 不为0，没有购买资格
            if (r == 1) {
                //库存不足
                return Result.fail("库存不足");
            } else {
                //一人一单
                return Result.fail("一人只能购买一次！");
            }
        }
        //2.2 为0，有购买资格

        //获取代理对象（事务）
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //3、返回订单id
        return Result.ok(orderId);
    }
    //@Override
    //public Result seckillVoucher(Long voucherId) {
    //    //获取用户
    //    Long userId = UserHolder.getUser().getId();
    //    //1、执行lua脚本
    //    Long result = stringRedisTemplate.execute(
    //            SECKILL_SCRIPT,
    //            Collections.emptyList(),
    //            voucherId.toString(), userId.toString()
    //    );
    //    int r = result.intValue();
    //    //2、判断结果是否为0
    //    if (r != 0) {
    //        //2.1 不为0，没有购买资格
    //        if (r == 1) {
    //            //库存不足
    //            return Result.fail("库存不足");
    //        } else {
    //            //一人一单
    //            return Result.fail("一人只能购买一次！");
    //        }
    //    }
    //
    //    //2.2 为0，有购买资格，把下单信息保存到阻塞队列
    //
    //    //创建订单
    //    VoucherOrder order = new VoucherOrder();
    //    //订单id
    //    long orderId = redisIdWorker.nextId("order");
    //    order.setId(orderId);
    //    //用户id
    //    order.setUserId(userId);
    //    //优惠券id
    //    order.setVoucherId(voucherId);
    //    //存入阻塞队列
    //    orderTasks.add(order);
    //
    //    //获取代理对象（事务）
    //    proxy = (IVoucherOrderService) AopContext.currentProxy();
    //    //3、返回订单id
    //    return Result.ok(orderId);
    //}

    private class VoucherOrderHandler implements Runnable {
        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true) {
                try {
                    //1、获取消息队列中的订单信息 xreadgroup group g1 c1 count 1 block 2000 streams streams.order >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    //2、判断消息获取是否成功
                    if(list == null || list.isEmpty()){
                        //2.1 如果获取失败，说明没有消息，继续下一次循环
                        continue;
                    }
                    //解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    //3、如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    //4、ACK确认 SACK streams.order g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    //1、获取pending-list中的订单信息 xreadgroup group g1 c1 count 1 streams streams.order 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    //2、判断消息获取是否成功
                    if(list == null || list.isEmpty()){
                        //2.1 如果获取失败，说明pending-list没有异常消息，结束循环
                        break;
                    }
                    //解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    //3、如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    //4、ACK确认 SACK streams.order g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常", e);
                    //此处不用做递归，因为while(true)，会自动再次进入循环
                }
            }
        }
    }
    @Override
    public Result createVoucherOrder(Long voucherId) {
        return null;
    }

    //private class VoucherOrderHandler implements Runnable {
    //    @Override
    //    public void run() {
    //        while (true) {
    //            try {
    //                //1、获取队列中的订单信息
    //                VoucherOrder voucherOrder = orderTasks.take();
    //                //2、创建订单
    //                handleVoucherOrder(voucherOrder);
    //            } catch (Exception e) {
    //                log.error("处理订单异常", e);
    //            }
    //
    //        }
    //    }
    //}

        private void handleVoucherOrder(VoucherOrder voucherOrder) {
            Long voucherId = voucherOrder.getVoucherId();
            Long userId = voucherOrder.getUserId();
            //创建锁对象
            //SimpleRedisLock lock = new SimpleRedisLock(stringRedisTemplate, "order:" + userId);
            RLock lock = redissonClient.getLock("lock:order:" + userId);
            //获取锁
            boolean isLock = lock.tryLock();
            if (!isLock) {
                log.error("不允许重复下单");
            }
            try {

                proxy.createVoucherOrder(voucherId);

            } finally {
                //释放锁
                lock.unlock();
            }
        }



        //@Override
        //public Result seckillVoucher(Long voucherId) {
        //    //1、查询优惠券
        //    SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //    //2、判断秒杀是否开始
        //    if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
        //        //还未开始
        //        Result.fail("还未开始");
        //    }
        //    //3、判断秒杀是否结束
        //    if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
        //        //现已结束
        //        Result.fail("现已结束");
        //    }
        //    //4、判断库存是否充足
        //    if (voucher.getStock()<1) {
        //        //库存不足
        //        Result.fail("库存不足");
        //    }
        //
        //    Long userId = UserHolder.getUser().getId();
        //    //创建锁对象
        //    //SimpleRedisLock lock = new SimpleRedisLock(stringRedisTemplate, "order:" + userId);
        //    RLock lock = redissonClient.getLock("lock:order:" + userId);
        //    //获取锁
        //    boolean isLock = lock.tryLock();
        //    if(!isLock){
        //        //获取锁失败，返回错误或重试
        //        return Result.fail("不允许重复下单");
        //    }
        //    //获取代理对象（事务）
        //    try {
        //        IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
        //        return proxy.createVoucherOrder(voucherId);
        //    } finally {
        //        //释放锁
        //
        //        lock.unlock();
        //    }
        //
        //}

        //@Transactional
        //public  Result createVoucherOrder(Long voucherId) {
        //
        //    //一人一单
        //    Long userId = UserHolder.getUser().getId();
        //
        //    //①查询订单
        //    int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
        //    //②判断是否存在
        //    if (count>0) {
        //        return Result.fail("用户已经购买过一次！");
        //    }
        //
        //    //5、扣减库存
        //    seckillVoucherService.update()
        //            .setSql("stock = stock - 1")
        //            .eq("voucher_id", voucherId).gt("stock",0)
        //            .update();
        //    //6、创建订单
        //    VoucherOrder order = new VoucherOrder();
        //    //6.1 订单id
        //    long orderId = redisIdWorker.nextId("order");
        //    order.setId(orderId);
        //    //6.2 用户id
        //
        //    order.setUserId(userId);
        //    //6.3 优惠券id
        //    order.setVoucherId(voucherId);
        //
        //    save(order);
        //    //7、返回订单id
        //    return Result.ok(orderId);
        //
        //}
    }

